TL81A Series 6061 Aluminum Hidden-Shackle Lock, is specifically designed and manufactured for any swinging handle hasp on the back of trailers. This specific lock takes security one step further, as the TL81A-Seal gives you the ability to hook on an additional seal between the lock and your trailer. The lock cannot be opened without breaking the seal, and this way you’ll know if someone has hacked, or tried to hack, into your trailer. Please be aware that the TL81A-Seal will not work on any intermodal container doors nor any swinging handle hasp that has an extra “rib” on the handle itself. For these situations, please purchase the “TL82A” product., Standard Rekeyable Brass Cylinder with Anti-Pick and Bump Resistant Technology, Made in the USA with Global Components, Includes PAC-Tether Capability.